An independent federal agency said Tuesday that it is investigating whether safety was compromised when a Palmdale air traffic control center lost radar and radio communications last week.
Investigators from the National Transportation Safety Board are interviewing controllers and reviewing data from systems at the Los Angeles Air Route Traffic Control Center, said Lauren Peduzzi, a spokeswoman for the board. The agency is trying to determine whether any of the roughly 200 airplanes that were in the center's air space during a two-hour power outage July 18 came too close to one another.
The Federal Aviation Administration, which operates the Palmdale center, has said that there was no loss of separation between any aircraft during the outage. The facility handles flights above 18,000 feet over Southern California and much of Nevada and Arizona
The incident snarled flight schedules and kept passengers waiting at several airports in the region, including Los Angeles International, Bob Hope and John Wayne. The outage delayed 348 flights across the country.
The outage left controllers briefly unable to see aircraft on radar screens or talk with pilots, after a surge-protection system designed to protect sensitive equipment from power spikes caused backup generators to fail.
Backup generators came on at about 4:19 p.m. after a truck downed power lines near the center.
They worked for about 75 minutes. Power was restored at 7:30 p.m.
On Tuesday, new details emerged about the outage's financial fallout for airlines and how the equipment malfunction inconvenienced passengers.
International carriers at LAX spent about $1.5 million to feed and house passengers when their flights were canceled in Los Angeles, or after they missed connections in other countries -- an amount equivalent to the costs that arise after a major snowstorm in the Midwest, said Frank Clark, executive director of the nonprofit organization that represents airlines operating from the Tom Bradley International Terminal.
"In many cases, these people had already been flying for a number of hours when they were diverted, such as a British Airways flight to Albuquerque, and then delayed for several hours," he said. "Then on the return British Airways flight, rather than a late afternoon departure, they didn't get out until 2 a.m., and passengers missed their connections and had to spend the night in London. The following day there weren't seats for them, so they had an added delay."
The losses to international carriers did not include additional expenses incurred for crews and aircraft being out of sequence, resulting in overtime and delays, he added.
During the outage, Southwest Airlines let passengers board several flights that had been held on the ground, only to tell travelers they had to get off.
The incidents occurred after a "slight miscommunication between Southwest and the tower," said Marilee McInnis, a Southwest spokeswoman.
"Always in a situation like this we absolutely hope for the best, we don't want to be stuck with an empty aircraft when our takeoff slot comes open," she said. "It's hard to balance technical glitches with customer service."
The carrier canceled 48 flights and diverted 26 others away from Southern California airports as a result of the outage.
Southwest was one of many airlines that spoke with FAA and airport officials Tuesday about how to improve communications during emergencies. About 83 people attended the debriefing at LAX.
The airlines, local airports and the FAA plan to form a group that will study how to keep more flights in operation during power outages at air traffic facilities.